Biomass production and phosphorus accumulation of potato as affected by phosphorus nutrition

Potato (Solanum tuberosum) generally requires high amounts of phosphate fertilizer to reach economically acceptable yields, particularly in soils originating from volcanic ash. This is a consequence of the potato plants low soot density and the slow soil diffusion rate of phosphorus (P) in these soils. Our objective was to evaluate the effect of P rates on tuber yield, biomass production, and distribution, biomass P accumulation and concentration, and P distribution in potato cv. Mexiquense. The experiment was carried out in an Andisol (7.8 mu g g(-1) Olsen-P) located at the east of Valle de Mexico. Fertilization rates were 0, 18, 41, 46, 69, 78, 90, 106, 113, 135, 150, 163, and 207 kg ha(-1) P, from ordinary superphosphate. Top growth and root biomass, tuber yield, P percentage and P accumulation in different plant parts were measured at harvest. Minimum and maximum average tuber yields were 8.4 and 18.0 Mg ha(-1); the plants absorbed 5.8 and 11.8 kg ha(-1) P, corresponding to 0 (control) and 207 bg ha(-1) P, respectively. Phosphorus fertilization had little influence on plant P concentration, where average concentrations in tuber and top growth were 0.20 and 0.24% P, respectively. By contrast, P accumulation increased with increasing P rates, but P distribution between tuber and top growth was dependent on the amount of P applied. The control treatment showed approximately 1:1 distribution of P between top growth and tuber, but as P rate increased, top growth P decreased and tuber P increased. When applying the highest P rate, 36% of P accumulated in the top growth and 64% in the tuber. The information obtained will permit decisions on the correct use of phosphate fertilizer for potato in Andisols of the Valle de Mexico.